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mm: fix the handling Non-LRU pages returned by follow_page

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The handling Non-LRU pages returned by follow_page() jumps directly, it
doesn't call put_page() to handle the reference count, since 'FOLL_GET'
flag for follow_page() has get_page() called.  Fix the zone device page
check by handling the page reference count correctly before returning.

And as David reviewed, "device pages are never PageKsm pages".  Drop this
zone device page check for break_ksm().

Since the zone device page can't be a transparent huge page, so drop the
redundant zone device page check for split_huge_pages_pid().  (by Miaohe)

Link: https://lkml.kernel.org/r/20220823135841.934465-3-haiyue.wang@intel.com
Fixes: 3218f8712d ("mm: handling Non-LRU pages returned by vm_normal_pages")
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Haiyue Wang 2022-08-23 21:58:41 +08:00 committed by Andrew Morton
parent ca3d76b0aa
commit f7091ed64e
3 changed files with 22 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
mm/huge_memory.c
View File

@ -3001,7 +3001,7 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start,
/* FOLL_DUMP to ignore special (like zero) pages */
page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP);
if (IS_ERR_OR_NULL(page) || is_zone_device_page(page))
if (IS_ERR_OR_NULL(page))
continue;
if (!is_transparent_hugepage(page))

12
mm/ksm.c
View File

@ -475,7 +475,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
cond_resched();
page = follow_page(vma, addr,
FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE);
if (IS_ERR_OR_NULL(page) || is_zone_device_page(page))
if (IS_ERR_OR_NULL(page))
break;
if (PageKsm(page))
ret = handle_mm_fault(vma, addr,
@ -560,12 +560,15 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
goto out;
page = follow_page(vma, addr, FOLL_GET);
if (IS_ERR_OR_NULL(page) || is_zone_device_page(page))
if (IS_ERR_OR_NULL(page))
goto out;
if (is_zone_device_page(page))
goto out_putpage;
if (PageAnon(page)) {
flush_anon_page(vma, page, addr);
flush_dcache_page(page);
} else {
out_putpage:
put_page(page);
out:
page = NULL;
@ -2322,11 +2325,13 @@ next_mm:
if (ksm_test_exit(mm))
break;
*page = follow_page(vma, ksm_scan.address, FOLL_GET);
if (IS_ERR_OR_NULL(*page) || is_zone_device_page(*page)) {
if (IS_ERR_OR_NULL(*page)) {
ksm_scan.address += PAGE_SIZE;
cond_resched();
continue;
}
if (is_zone_device_page(*page))
goto next_page;
if (PageAnon(*page)) {
flush_anon_page(vma, *page, ksm_scan.address);
flush_dcache_page(*page);
@ -2341,6 +2346,7 @@ next_mm:
mmap_read_unlock(mm);
return rmap_item;
}
next_page:
put_page(*page);
ksm_scan.address += PAGE_SIZE;
cond_resched();

19
mm/migrate.c
View File

@ -1691,9 +1691,12 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
goto out;
err = -ENOENT;
if (!page || is_zone_device_page(page))
if (!page)
goto out;
if (is_zone_device_page(page))
goto out_putpage;
err = 0;
if (page_to_nid(page) == node)
goto out_putpage;
@ -1891,13 +1894,15 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
if (IS_ERR(page))
goto set_status;
if (page && !is_zone_device_page(page)) {
err = -ENOENT;
if (!page)
goto set_status;
if (!is_zone_device_page(page))
err = page_to_nid(page);
if (foll_flags & FOLL_GET)
put_page(page);
} else {
err = -ENOENT;
}
if (foll_flags & FOLL_GET)
put_page(page);
set_status:
*status = err;